Read the instructions for the torque spec! The torque spec is less than the standard AR-15/M-16 value. I bought an open box return at my LGS and it was missing the instructions. The teeth on the barrel nut broke easily when I applied standard torque. Fortunately Midwest sells replacement barrel nuts with instruction sheets. I torqued it on correctly and it works just fine. Imagine that. I prefer the barrel nuts for the G4 and Combat series, but this worked OK.